This invention relates to pallets used to package, store, and handle materials and more specifically to such pallets having plastic legs according to the invention.
Pallets have traditionally been formed of wood. Wood pallets, however, have many disadvantages. For example, they are subject to breakage and thus are not reusable over extended periods of time. Wood pallets, as they will deteriorate if left exposed to the elements, must be stored indoors when not in use and so take up a considerable amount of valuable floor space in the warehouse. In an effort to solve some of the problems associated with wood pallets, plastic pallets have been developed and employed with some degree of success.
In one generally successful form of plastic pallet design, an upper panel or platform is formed by fusing together upper and lower plastic sheets to form a reinforced double wall or "twin sheet" structure.
Some pallets consist of a single upper panel constituting a load-bearing platform with a plurality of legs extending downward from the platform to maintain it in spaced relation to a support surface on which the legs rest. Other pallets consist of two panels, the first constituting an upper platform structure and the second a lower base structure, with a plurality of legs or spacers separating the two. In both of the foregoing types of pallets, referred to as single faced and double faced pallets respectively, the legs are distributed over the undersurface of the platform structure in a number and density sufficient to adequately support the weight likely to be carried by a particular pallet design when used in its intended manner. For example, for a rectangular pallet, there will typically be nine legs with one located at each corner of the pallet, one midway along each of the pallet sides, and one at the center of the pallet.
The legs are typically formed by molding at each location where a leg is desired a large downwardly extending protrusion in both the upper and lower plastic sheets of the twin sheet structure. The leg protrusion of the top sheet fits inside of and is fused to that of the lower sheet, and the resulting leg extends downwardly substantially below the lower surface of the platform structure.
A disadvantage of this construction is that the pallet must be fabricated on a mold that can only produce a pallet having one predetermined configuration of legs. Thus, the production of a range of different pallets optimized for specific applications and having different numbers and patterns of legs requires the pallet fabricator to invest in a large number of different molds. Further, the leg structures are of necessity formed of the same thickness plastic material as the platform structure so that the structural requirements and concerns of the leg structures may not be individually addressed but, rather, must be address in consideration of the often divergent structural requirements and concerns of the platform structure.